China expressed “strong dissatisfaction” with India on Thursday after the recent crash of an Indian drone in what the Chinese military said was Chinese territory.

India said on Thursday a “UAV on a regular training mission” lost control and crossed the LAC in Sikkim, hours after China expressed “strong dissatisfaction”over an Indian drone crashing in its territory.

China said the drone crashed in “recent days” but did not give a location.

Reacting to a Xinhua news article on the incident, the Indian defence ministry said: “An Indian UAV which was on a regular training mission inside the Indian territory lost contact with the ground control due to some technical problem and crossed over the LAC in the Sikkim Sector. As per standard protocol, the Indian border security personnel immediately alerted their Chinese counterparts to locate the UAV.”

The incident comes about two months after the two governments resolved a 70-odd day standoff between border troops near the Sikkim boundary.

On Thursday, China said the entry of the drone violated its territorial sovereignty. “China’s border defence forces took a professional and responsible attitude in conducting an inspection of the device,” said Zhang Shuili, a senior military official in China’s western battle zone command.

The Indian defence ministry said later: “…the Chinese side reverted with the location details of the UAV. The exact cause of the incident is under investigation. The matter is being dealt with in accordance with the established protocols through institutional mechanisms to deal with situations along the India-China border areas.”

Incidents involving drones have erupted before between India, China and Pakistan in the last few years.

In 2015, Pakistan armed forces shot down a drone near the Line of Control with India, which later turned out to have been manufactured in China.

The drone was “recognised in Beijing as the Chinese-made DJI phantom 3”, the state media had then reported.